1. Field of the Invention
The present invention relates to a motor drive circuit.
2. Description of the Related Art
In electronic devices such as a printer, a plurality of motors are used in order to drive a head mechanism, a paper feed mechanism, and the like. Thus, in such an electronic device, a motor drive circuit capable of driving a plurality of motors may be used (See Japanese Patent Laid-Open Publication No. 2004-14940, for example).
FIG. 4 is an example of a motor drive circuit 200 configured to drive motors 300 and 301, which are DC motors. An H-bridge circuit 210 supplies an electric current from a terminal A1 to a terminal B1 when the motor 300 is rotated normally, and supplies an electric current from the terminal B1 to the terminal A1 when the motor 300 is rotated reversely, based on an instruction from a microcomputer 310. An H-bridge circuit 211 supplies an electric current from a terminal A2 to a terminal B2 when the motor 301 is rotated normally, and supplies an electric current from a terminal B2 to a terminal A2 when the motor 301 is rotated reversely, based on an instruction from a microcomputer 310. When the motors 300 and 301 are to be stopped rotating, the microcomputer 310 controls the H-bridge circuits 210 and 211 so as to stop the current to be supplied to the motors 300 and 301.
As a result, the motors 300 and 301 rotate in accordance with the instruction from the microcomputer 310.
If a current to be supplied to the motor is to be increased, for example, one motor 302 might be driven by the two H-bridge circuits 210 and 211, as illustrated in FIG. 5. In order to rotate the motor 302 in a desired direction, the directions of the currents need to be matched which are supplied from the H-bridge circuits 210 and 211 to the motor 302. That is, the terminals A1 and A2 need to be connected, while the terminals B1 and B2 need to be connected. As a result, if the common motor 302 (motor coil) is to be driven by the motor drive circuit 200, wiring on a substrate mounted with the motor 302 results in being complicated.